As we have mentioned in other articles and reviews, the first place we look when opening a power supply for a hint about its quality, is its filtering stage. The recommended components for this stage are two ferrite coils, two ceramic capacitors (Y capacitors, usually blue), one metalized polyester capacitor (X capacitor), and one MOV (Metal-Oxide Varistor). Very low-end power supplies use fewer components, usually removing the MOV and the first coil.

This power supply has all the required components except for the MOV, which is in charge of removing spikes coming from the power grid. On the other hand, it has two Y capacitors and one X capacitor more than the minimum required.

click to enlargeFigure 8: Transient filtering stage (part 1)

click to enlargeFigure 9: Transient filtering stage (part 2)

Now let’s have a more detailed discussion of the components used in the Sentey Golden Steel Power 850 W.